1. Field of the Invention
The present invention relates to pipe handling systems used in drilling wells on land or offshore.
2. Description of the Related Art
A tubular to be used in drilling is typically first lifted with a crane from a horizontal pipe storage rack located in the pipe deck area outside the drilling structure or derrick on the drilling deck, and then placed horizontally with one end of the tubular near the V-door of the derrick. The tubular may then be moved through the V-door with rig equipment and rotated into the vertical position for either stand building or direct insertion through the well center. The traditional tubular handling process is inefficient and raises safety issues.
Although several horizontal pipe handling systems have been proposed, they rely upon various mechanical pipe moving devices to move a pipe from the top of a pipe rack. U.S. Pat. No. 3,734,210 proposes a pipe transfer assembly having a support arm with a pipe flipper operated with an air cylinder to engage a pipe at the top of a rack and release and push it to a handling arm. Pub. No. US 2008/0101891 proposes a pipe rack with a lifting block mechanism that lifts a pipe over an elevated stop mechanism for it to move to a motorized arm mechanism that rotates and lowers the pipe to an adjacent erector system. Pub. No. US 2007/0031215 proposes a vertically moveable pipe moving assembly with an extendable finger that lifts a tubular over the top of a pipe rack and allows it to move to an attached rotatable arm for movement with the pipe moving assembly vertically down the side of the pipe rack where the rotatable arm rotates to move the pipe to an erector system. U.S. Pat. No. 6,311,788 proposes a vertically moveable pipe removal device with an extendable and rotatable gripping claw to lift and remove a drilling rod part from a drilling rod magazine. U.S. Pat. No. 7,537,424 proposes a pivotable and extendable pipe transfer arm to lift and remove a pipe section from a pipe storage bin. U.S. Pat. No. 6,860,694 proposes a picking column with picking arms to lift and remove a pipe from the top of a pipe rack. Pub. No. US 2003/0196791 proposes a vertical conveyor system with shovel arms that lift and remove a pipe from the top of a pipe rack and transports the pipe up to a series of horizontal conveyor systems.
Pub. No. US 2008/0202812 proposes a pipe rack that preferably stores five tubulars that has a hydraulically operated indexing arm assembly that rolls the tubulars toward a pick up location and hydraulically activated separators isolate one tubular that is to be gripped by a horizontal to vertical arm (see '812 publication ¶60).
The above discussed U.S. Pat. Nos. 3,734,210; 6,311,788; 6,860,694; and 7,537,424; and Pub. Nos. US 2003/0196791; 2007/0031215; 2008/0101891; and 2008/0202812 are hereby incorporated by reference for all purposes in their entirety.
Handling numerous heavy tubulars of different sizes in severe drilling environments is known to be challenging for and destructive to mechanical devices. Valuable rig time is lost when the mechanical devices require maintenance and/or repair. A need exists for a pipe handling system that minimizes mechanical devices that require maintenance and/or repair. A need exists for a pipe handling system that may be safely operated with minimal human intervention while creating rig use efficiencies. It would also be desirable to be able to selectively handle tubulars from different tiers of a pipe rack, and to have a reliable way to move a tubular toward the well center.